Monopolar electrosurgical trocar

ABSTRACT

In the present invention, a surgical trocar is adapted to conduct monopolar electrosurgical energy to specially adapted cordless monopolar electrosurgical instruments. In one embodiment of the present invention, an electrosurgical trocar includes a cannula, an electrosurgical adapter and a locking connector adapted to connect the cannula to the electrosurgical adapter.

This is a continuation-in-part of application Ser. No. 08,856,534, filedMay 14, 1997, which is hereby incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates, in general, to an improvedelectrosurgical trocar adapted to provide electrosurgical energy tospecially adapted cordless electrosurgical instruments used with theelectrosurgical trocar and, more particularly, to a monopolarelectrosurgical trocar and trocar adapter.

BACKGROUND OF THE INVENTION

The surgical trocar has become the mainstay in the development andacceptance of endoscopic surgical procedures. Endoscopic surgeryinvolves the performance of surgery through a number of openings havinga relatively small diameter. These openings are made with the trocar,which typically includes a trocar obturator and a trocar cannula. Theobturator is the piercing implement which punctures the body wall tomake the opening. Once the puncture is made, the obturator is withdrawnfrom the cannula. The cannula then provides a small diameter passagewayinto and through the body wall to provide access for additional surgicalinstrumentation to the surgical site. The function, structure andoperation of a typical trocar is described in detail in U.S. Pat. No.5,387,197, which is hereby incorporated herein by reference.

Such additional surgical instruments may include, for example, bipolaror monopolar electrosurgical instruments which utilize radio frequencyelectrosurgical energy. Known electrosurgical instruments include, forexample, bipolar forceps, bipolar scissors, monopolar-hook,monopolar-scissors and, bipolar endocutters. Each of those instrumentshas an electrosurgical end effector which is adapted to treat tissuethrough the application of electrosurgical (e.g. radio frequency or RF)energy to tissue which is brought in contact with the electrosurgicalend effector. Most known electrosurgical instruments are connected byelectrical cords to electrosurgical generators. The structure andoperation of a typical bipolar cutter/stapler ("bipolar endocutter") isdescribed in U.S. Pat. No. 5,403,312 which is hereby incorporated hereinby reference. The structure and operation of typical monopolarelectrosurgical instruments is described in U.S. Pat. No. 5,207,691 andU.S. Pat. No. 5,273,524 which are hereby incorporated herein byreference.

Electrosurgical generators, such as the Force II generator which isavailable from Valley Lab of Bolder Colo., supply electrical energy tothe electrosurgical instruments through electrical cords. The electricalcords, being attached directly to the electrosurgical instrument, maymake the electrosurgical instrument inconvenient to use. Alternatively,electrical cords may cause undesirable delays as one electrosurgicalinstrument is unplugged from the generator and another is plugged in.Thus, it would be advantageous to design a cordless electrosurgicalinstrument. However, such a cordless electrosurgical instrument wouldhave to be connected to the electrosurgical generator through somealternate arrangement. Therefore, it would also be advantageous todesign a trocar or a trocar adapter which is adapted to conductelectrosurgical energy to specially designed cordless electrosurgicalinstruments. In particular, it would be advantageous to design amonopolar electrosurgical trocar or trocar adapter particularly adaptedfor use with monopolar electrosurgical instruments.

SUMMARY OF THE INVENTION

In the present invention, a monopolar surgical trocar or trocar adapteris adapted to conduct electrosurgical energy to specially adaptedcordless electrosurgical instruments. In one embodiment of the presentinvention, an electrosurgical trocar includes a cannula, anelectrosurgical adapter and a locking connector adapted to connect thecannula to the electrosurgical adapter. The cannula is an elongated tubewhich may be inserted into a body cavity, duct or vessel. Theelectrosurgical adapter includes a housing with an elongated centralaperture, at least one electrical contact positioned in and extendingaxially along the elongated aperture, at least one internal electricalconductor, at least one external conductor, an outer housing and anelectrical cord. An electrosurgical trocar or trocar adapter accordingto the present invention may also include a compression mechanism.

In a further embodiment of the present invention, the adapter apertureis formed by an aperture wall positioned in the adapter housing. Theelectrical contact is positioned in and extends axially along theaperture, forming at least a portion of the walls of the aperture. Theelectrical contact may be divided into two pieces within the aperture.The internal electrical conductor connects the electrical contact to theexternal connector. The compression mechanism biases the pieces of theelectrical contact toward the center of the adapter aperture. Anelectrical cord is connected to the external connector such that theelectrical cord may be used to plug the adapter into one output of anelectrosurgical generator. A return electrode may be affixed to the skinof the patient as in a conventional monopolar arrangement.

In a further embodiment of the present invention, the electrical contactis divided into a first stator plate and a second stator plate. Thesecond stator plate is positioned opposite the first stator plate. Thesecond stator plate is electrically connected to the first stator plate.The compression member includes one or more compression rings positionedaround the first and second electrical contacts.

In a further embodiment of the present invention, the electrosurgicaltrocar includes a locking connector which connects the cannula to theadapter. In this embodiment of the invention, the adapter includes firstand second locking cleats extending from the distal end of theconnector. The cannula includes receptors such as indentations or ribswhich hold the distal ends of the locking cleats in place, thus holdingthe connector in contact with the cannula.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. The invention itself, however, both as toorganization and methods of operation, together with further objects andadvantages thereof, may best be understood by reference to the followingdescription, taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a perspective view of a monopolar electrosurgical trocaraccording to the present invention.

FIG. 2 is a plan view section taken through the electrosurgical trocarillustrated in FIG. 1.

FIG. 3 is a section view taken along line 3--3 of FIG. 2.

FIG. 4 is a perspective view of a cordless electrosurgical instrumentaccording to the present invention.

FIG. 5 is an exploded perspective view of the distal end of the cordlesselectrosurgical instrument illustrated in FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a perspective view of a monopolar electrosurgical trocaraccording to the present invention. Electrosurgical trocar 11 includestrocar cannula 8 and electrosurgical adapter 14. Electrosurgical trocar11 may also include an obturator assembly (not shown) such as the oneillustrated in U.S. Pat. No. 5,387,197, which has been previouslyincorporated herein by reference. Trocar cannula 8 includes cannulahousing 12 and cannula tube 10, extending from housing 12.Electrosurgical adapter 14 includes an adapter housing 15, lockingconnector 17 and an electric cord 18. In the embodiment of the inventionillustrated in FIG. 1, electrosurgical adapter 14 is connected to trocarcannula 8 by locking connector 17. Locking connector 17 includes lockingcleat 20 and release button 22. It will be apparent that electrosurgicaladapter 14 may be integrated directly into trocar cannula 8, thuseliminating the need for locking connector 17.

FIG. 2 is a plain view section taken through electrosurgical trocar 11.In FIG. 2, cannula housing 12 includes flapper valve 34 and ring gasket33. Electrosurgical adapter 14 includes central aperture 19, frontflange 25 and base flange 24. Aperture 19 is an elongated aperture forreceiving working instruments such as endoscopic electrosurgicalinstruments. Electrosurgical adapter 14 further includes one or moreinterior electrical contacts which, in the embodiment illustrated inFIGS. 2 and 3, comprise stator plates 28 and 29. At least a portion ofthe interior wall of central aperture 19 is formed by upper insulator 30and upper stator plate 28. Upper insulator 30 is positioned againstfront flange 25 and base flange 24. Compression member 32 is, in thepresent embodiment, an o-ring which is positioned outside of upperinsulator 30 to bias upper insulator 30 and upper stator plate 28 towardthe center of central aperture 19. Compression member 32 may also be,for example, a spring, a flexible sleeve, a plurality of o-rings or anyother suitable biasing member.

FIG. 3 is a sectional view of electrosurgical adapter 14 taken alongline 3--3 of FIG. 2. Central aperture 19 is defined by aperture interiorwall 21. The portion of interior wall 21 visible in FIG. 3 is formed, atleast in part, by upper contact surface 60 of upper stator plate 28 andlower contact surface 61 of lower stator plate 29. Upper stator plate 28and lower stator plate 29 are positioned on, and may be electricallyinsulated from one another by, upper insulator 30 and lower insulator31, respectively. Alternatively, upper stator plate 28 and lower statorplate 29 may be in electrical contact. In a further alternativeembodiment, stator plate 28 and stator plate 29 may be joined to form asingle electrode, which single electrode may or may not include acompression gap 39. In order to ensure that contact is maintained,compression gap 39 must be relatively small and, in particular,compression gap 39 should be smaller than the diameter of the contactelectrode on any electrosurgical instrument used with electrosurgicaltrocar 11. Compression member 32 surrounds upper insulator 30 and lowerinsulator 31. Compression member 32, which is an o-ring in theembodiment of FIGS. 2-3, biases upper insulator 30 and lower insulator31 toward the center of central aperture 19. Electric cord 18 isconnected to upper stator plate 28 by upper conductor 36 and upperstator tab 26. Electric cord 18 is connected to lower stator plate 29 bylower conductor 38 and lower stator tab 27. Upper conductor 36 may beelectrically connected to lower conductor 38 such that upper statorplate 28 and lower stator plate 29 are electrically common. Base flange24, which is part of adapter housing 15, holds upper insulator 30 andlower insulator 31 in place. Strain relief 23 protects electric cord 18as it passes through adapter housing 15. Electric cord 18 may be pluggedinto a suitable electrosurgical generator using, for example, amonopolar plug 64.

FIG. 4 is a perspective view of a cordless monopolar electrosurgicalinstrument which may be, for example, a monopolar cutter/stapler. InFIG. 4, electrosurgical instrument 16 includes handle 72, closure tube50 and end effector 57. Closure tube 50 is elongated to facilitateinsertion of end effector 57 through a trocar cannula (such as cannulatube 10 of electrosurgical trocar 11), thus facilitating the use ofelectrosurgical instrument 16 in endoscopic or laparoscopic surgicalprocedures. Handle 72, which is located at the proximal end ofinstrument 16, includes grasping trigger 74, firing trigger 76 andrelease trigger 78. Closure tube 50, which connects handle 72 to endeffector 57, includes rotation knob 70, first contact insulator 40,instrument electrode contact 42 and outer tube 51. End effector 57,which is located at the distal end of closure tube 50 includes anvil 58and cartridge channel 88 and may further include staple cartridge 68.Electrosurgical instrument 16 is similar in structure and operation tothe endoscopic electrocautery linear cutting and stapling instrumentillustrated and described in U.S. Pat. No. 5,403,312, which has beenpreviously incorporated herein by reference, except that electrosurgicalinstrument 16, as illustrated in FIG. 4, is adapted to work as acordless monopolar instrument. In electrosurgical instrument 16,electrosurgical energy is supplied to the instrument through instrumentelectrode contact 42.

FIG. 5 is an exploded perspective view of the distal end ofelectrosurgical instrument 16. In FIG. 5, outer tube 51 is positionedover closure tube 50. In the instruments illustrated in FIGS. 4 and 5,closure tube 50 is electrically conductive and outer tube 51 isconstructed of an electrically insulating material. Instrument electrodecontact 42, which penetrates first contact insulator 40, extends throughopening 53 in outer tube 51. First contact insulator 40 electricallyisolates contact 42 from closure tube 50. In an alternateelectrosurgical instrument, closure tube 50 may be constructed of aninsulating material. Conductor 48 passes through closure tube 50 fromelectrode assembly 52 to instrument electrode contact 42, electricallyconnecting electrode assembly 52 to contact 42. Electrode assembly 52 ispositioned in anvil 58. Electrode assembly 52 may be electricallyinsulated from anvil 58 and closure tube 50 to prevent electrodeassembly 52 from shorting to anvil 58 or closure tube 50. Conductor 48may be insulated to prevent it from shorting to closure tube 50 or anyof the mechanisms in closure tube 50.

In the cordless electrosurgical instrument illustrated in FIGS. 4 and 5,knife 90 is connected to wedge assembly 82 and wedge assembly 82 isconnected to firing rod 84, which, in turn, is operatively connected tofiring trigger 76. Closure tube 50 is operatively connected to rotationknob 70, grasping trigger 74 and release trigger 78. Wedge guide 80 isfitted over wedge block assembly 82 to guide wedge block assembly 82 asfiring rod 84 moves wedge block assembly 82. The structure and operationof the mechanical features of the device illustrated in FIGS. 4 and 5may be better understood with reference to the mechanical cutting andstapling instrument illustrated and described in U.S. Pat. No. 5,597,107which is hereby incorporated herein by reference.

In the device illustrated in FIGS. 4 and 5, electrode assembly 52 actsas a primary electrode and a secondary or return electrode (not shown)is affixed to the skin of the patient in, for example, the mannerillustrated in U.S. Pat. No. 5,207,691 which has been previouslyincorporated herein by reference. When electrically conductive tissue isgrasped by end effector 57 and an electrosurgical generator is connectedto first instrument electrode contact 42 and a second electrode isconnected to the patient's skin, electrosurgical energy will flowthrough the grasped tissue to the external electrode, coagulating thegrasped tissue.

In operation, trocar cannula 8 is used with a conventional trocarorbitor (not shown) to penetrate the wall of a body cavity such as, forexample, the abdominal wall of a human being. After the body wall ispenetrated, the obturator assembly is withdrawn from trocar cannula 8,and the cannula is used as an access portal for the passage of variousendoscopic instruments to provide access to internal organs. Where theendoscopic instrument to be used is a monopolar cordless electrosurgicalinstrument such as electrosurgical instrument 16, electrosurgicaladapter 14 may be attached to trocar cannula 8. Once electrosurgicaladapter 14 is attached to trocar cannula 8 and electric cord 18 isattached to a suitable electrosurgical generator (not shown),electrosurgical trocar 11 may be used to provide electrosurgical energyto cordless electrosurgical instruments such as monopolarelectrosurgical instrument 16.

When a cordless electrosurgical instrument such as monopolarelectrosurgical instrument 16 is inserted into a body cavity throughelectrosurgical trocar 11, end effector 57 passes through trocar cannula8 and into the body cavity while most of closure tube 50 remains in thetrocar. Handle 72, which is outside of trocar 11, is manipulated by thesurgeon to control the position of end effector 57.

Electrosurgical energy is provided to instrument 16 by the interactionof contact 42 with the stator plates 28 and 29. The diameter of centralaperture 19 generally corresponds with the outer diameter of closuretube 50, including outer tube 51, so that closure tube 50 slides throughcentral aperture 19 and the interior of cannula tube 10. Contact 42,being raised above the surface of closure tube 50 and outer tube 51,will scrape against stator plates 28 and 29 as closure tube 50 passesthrough aperture 19. Compression member 32 will ensure that statorplates 28 and 29 maintain electrical contact with contact 42,maintaining a good electrical connection between the stator plates inadapter 14 and the contact point on instrument 16. Electrical contactwill be maintained so long as contact 42 is positioned in centralaperture 19 opposite at least one of stator plates 28 and 29. Electricalcontact may be enhanced by using multiple contact points on instrument16.

With contact 42 in contact with one of stator plates 28 and 29,electrosurgical energy may be supplied to electrosurgical trocar 11through electric cord 18. The electrosurgical energy passes throughconductors 36 and 38, stator tabs 26 and 27 and stator plates 28 and 29into instrument 16 via contact 42. Electrosurgical energy supplied toinstrument 16 via contact 42 may be supplied to end effector 57 via thecircuit formed by first instrument electrode contact 42, conductor 48,and electrode assembly 52. This circuit is completed when tissue orother conductive material is grasped by end effector 57, providing apath from electrode assembly 52 to the grasped or touched tissue andthrough the patient to an external pad electrode. One or more switchesmay be included at any point in this circuit to control the flow ofelectricity to end effectors 57.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. Accordingly, it isintended that the invention be limited only by the spirit and scope ofthe appended claims.

What is claimed is:
 1. An electrosurgical adapter wherein theelectrosurgical adapter comprises:a) an aperture wall surrounding anelongated central aperture extending from a first end of said adapter toa second end of said adapter; b) a first electrical contact positionedin and extending axially along said elongated aperture wherein saidfirst electrical contact comprises:i) a first stator plate, wherein saidfirst stator plate comprises a first portion of said aperture wall; ii)a second stator plate electrically connected to said first stator plate,wherein said second stator plate comprises a second portion of saidaperture wall; c) a first electrical conductor connecting said firstelectrical contact to a first external connector, d) an outer housingsurrounding said aperture and said first electrical contact; and e) anelectrical cord connected to said first external connector and extendingfrom said outer housing.
 2. An electrosurgical adapter according toclaim 1 wherein said adapter further comprises a compression mechanismadapted to bias said electrical contact toward the center of saidaperture and said compression mechanism comprises a compression membersurrounding said stator plates.
 3. An electrosurgical adapter accordingto claim 2 wherein said compression member comprises one or morecompression rings.
 4. An electrosurgical adapter wherein theelectrosurgical adapter comprises:a) an aperture wall surrounding anelongated central aperture extending from a first end of said adapter toa second end of said adapter; b) a first electrical contact positionedin and extending axially along said elongated aperture, wherein saidfirst electrical contact comprises:i) a first stator plate, wherein saidfirst stator plate comprises a first portion of said aperture wall; ii)a second stator plate electrically connected to said first stator plate,wherein said second stator plate comprises a second portion of saidaperture wall; c) a first electrical conductor connecting said firstelectrical contact to a first external connector; d) a compressionmechanism wherein said compression mechanism is adapted to bias saidfirst and second stator plates toward the center of said aperture, saidcompression mechanism comprising a compression member surrounding saidstator plates, wherein said compression member comprises one or morecompression rings; e) an outer housing surrounding said aperture andsaid first electrical contact; and f) an electrical cord connected tosaid first external connector and extending from said outer housing. 5.An electrosurgical trocar, including a trocar adapter, wherein saidadapter comprises:a) an aperture wall surrounding an elongated centralaperture extending from a first end of said adapter to a second end ofsaid adapter; b) a first electrical contact positioned in and extendingaxially along said elongated aperture wherein said first electricalcontact comprises:i) a first stator plate, wherein said first statorplate comprises a first portion of said aperture wall; and ii) a secondstator plate electrically connected to said first stator plate, whereinsaid second stator plate comprises a second portion of said aperturewall; e) a first electrical conductor connecting said first electricalcontact to a first external connector; f) an outer housing surroundingsaid aperture and said first electrical contact; and g) an electricalcord connected to said first external connector and extending from saidouter housing.
 6. An electrosurgical trocar according to claim 5,wherein said compression mechanism comprises a compression membersurrounding said stator plates.
 7. An electrosurgical trocar accordingto claim 6, wherein said compression member comprises one or morecompression rings.
 8. An electrosurgical adapter wherein theelectrosurgical adapter comprises:a) an aperature wall surrounding anelongated central aperture including a central axis extending from afirst end of said adapter to a second end of said adapter; b) firstelectrical contact means for providing electrical energy to instrumentsplaced in said aperture, said first contact means being positioned inand extend axially along said elongated aperture wherein said firstelectrical contact means are electrically connected; c) a firstelectrical conductor connecting said first electrical contact means to afirst external connector means for connecting said first electricalconductor to an external source of electrical energy; d) an outerhousing surrounding said aperture and said first electrical contactmeans; and e) an electrical cord connected to said first externalconnector means and extending from said outer housing.
 9. Anelectrosurgical adapter according to claim 8, wherein said first andsecond electrical contact means comprise:a) a first stator plate,wherein said first stator plate comprises a first portion of saidaperture wall; and b) a second stator plate electrically connected tosaid first stator plate, wherein said second stator plate comprises asecond portion of said aperture wall.
 10. An electrosurgical adapteraccording to claim 8 wherein said adapter further comprises acompression means adapted to bias said first electrical contact meanstowards said central axis of said aperture.
 11. An electrosurgicaladapter according to claim 10 wherein said compression member comprisesone or more compression ring means for providing substantially equalpressure around said aperture.